Cam Button in Stock Timing Cover

[krazy86t]

I've read several threads on upgrading spring-loaded camhaft thrust button to spring-loaded roller version when removing front timing cover. I bought a NAPA 9-5189 spring-loaded roller button for this purpose. Car is TR @ 135k with stock camshaft, and had stock cam button with plastic head.

A couple questions:
1) timing cover recess where stock cam button was located is 1.045" diameter, but new cam button is 0.740" diameter. Is the smaller OD button ok for larger cam button hole in the cover?

2) The old cam button wore a cone profile into the timing cover hole area. Some old TB.com threads recommend sanding or machining this area flat, while others claim this isn't necessary. I think the flat surface would improve the ability for the roller button to remain located in the center of the cam shaft rotation axis, but i'm interested in more experienced opinions than mine.

Thanks!

 

[earlbrown]

It supposed to have a round platform a little bit above flush. How far from this is yours?...

Depending on how bad the cone is, you probably want to put in on a mill and spot face it flat and true.

 

[krazy86t]

See attachment for condition of my front cover. Definitely no raised platform. The outer edge of the hole is ~0.065" deep. i could spot face center of hole on a mill to get a 0.75" diameter flat surface for the NAPA cam button (0.74" diam). This surface would probably be 30-40 thousands below the surrounding front cover surface.

BTW - definitely appreciate your write-up on front cover mods! prepping this timing cover for those, but thought i better figure out the cam thrust button issue first.

 

[earlbrown]

If it's that deep you might want to set up a thickness gauge. There's water behind that spot and the LAST thing you want is to strike green gold while running.

 

[krazy86t]

I cleaned-up the cam thrust button hole with a 7/8" end mill. The hole is now flat for the roller button surface and 0.055" deep in the timing cover. I measured the thickness of the aluminum casting behind the hole at 0.105-0.110" to the thinnest point on the water pump side. Original thickness would have been approx. 0.160"

also sanded the oil pump cover because it was slightly grooved and not flat. unfortunately removing a few thousands from the surface revealed 2 buried flaws in the casting. The small holes in the surface are approx 0.03" dia.

looks like i should have sent $300 to TAPerf and i'd already have a new front cover, oil pump cover and gears.

 

[earlbrown]

You found multiple cavities that are .030" deep in your filter adapter?

Nice slight there at the end. It was a nice touch.

 

[krazy86t]

Sorry - last statement not intending to slight you.

My meaning: slightly frustrating to spend time cleaning something up to find out it is on the edge of garbage due to too many years of abuse. The small amount of machining was fun. 3 hours with various solvents removing 25 years of oil, grit, dirt, etc. = not fun.

2 small casting cavities on gear side smooth surface of oil pump cover.

 

[krazy86t]

pic of the oil pump cover after sanding flat. the black spots are small holes in casting surface. junk?

TAPerf has new ones - or thrust plate kit from Rock auto, napa, etc.